Connect points of motion tracks with (smoothed) lines
Tracking information creates a constraint. 

To convert constraints into keyframes, open the constraint section of the properties window and press Constraint to f-Curve



The tracking information will be converted to keyframes, the curves for those keyframes can be displayed and manipulated on the Graph Editor.



There are a few built in tools to clean up curves in the key menu of the Graph Editor.

Here's the same motion path after applying the "Clean Keyframes" function: